A three-directional strain in-situ monitoring system in a borehole

Abstract

The present application provides a kind of in-situ monitoring system of three-way strain in borehole, comprising: installation main rod, for fixing hole cleaning limiting disc and expansion directional strain monitoring cylinder to the preselected measuring point position;Hole cleaning limiting disc is used for when expansion directional strain monitoring cylinder enters hole, and expansion directional strain monitoring cylinder is guaranteed installation main rod and in-hole centering;Expansion anchor plug is used for expansion directional strain monitoring cylinder after entering hole, and expansion directional strain monitoring cylinder is installed in measuring point position;Expansion directional strain monitoring cylinder, the expansion directional strain monitoring cylinder includes borehole radial strain monitoring system, borehole axial strain monitoring system and positioning device.The present application has simple structure, low cost, and is convenient to install and use, and can quickly realize in-hole strain in-situ monitoring.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of tunnels and underground engineering. In particular, it relates to a three-dimensional in-situ monitoring device for drilling in complex surrounding rock of underground engineering such as tunnels and roadways, and more particularly, it relates to a three-dimensional in-situ monitoring system for drilling and a method of use thereof. BACKGROUND

[0002] At present, drilling strain monitoring is the main method for observing the internal stress and strain state of surrounding rock in underground engineering such as tunnels and roadways with high precision. The observation results are strong evidence for analyzing the deformation and failure characteristics of the surrounding rock and the stability of the surrounding rock, and are key empirical data for further studying the internal stress and deformation mechanism of the surrounding rock. However, during the construction of underground engineering such as tunnels and roadways, the drilling is usually deep and has a small diameter, making it difficult to install equipment in the hole. In addition, after the excavation of tunnels and roadways, the internal stress of the surrounding rock is redistributed, the stress on the surrounding rock changes, and the surrounding rock in the drilling may produce local rock debris peeling and hole collapse, which seriously affects the deformation coupling between the strain monitoring equipment in the hole and the drilling wall, and affects the monitoring precision. In addition, the problems of water vapor condensation and dust invasion in the drilling seriously affect the service life and observation accuracy of the in-hole monitoring equipment such as drilling strain monitoring. At the same time, the rough hole wall in the drilling also causes wear and tear to the equipment in the hole, threatening the installation and use of high-precision in-hole monitoring equipment, and seriously affecting the application of in-hole drilling in underground engineering research.

[0003] In view of the above problems, and in view of the fact that there is currently no in-hole strain monitoring equipment that can better solve the above problems, it is necessary to develop new drilling strain monitoring devices that can ensure long-term high-precision observation of the internal strain state of the surrounding rock in underground rock engineering such as tunnels and roadways, which is beneficial to improving the observation effect of the surrounding rock in the hole and the reliability of the observation results, and is a necessary requirement for in-depth study of the internal stress and deformation evolution of the surrounding rock in tunnels and roadways, and has important significance for the study of medium and long-term stress and deformation characteristics of the surrounding rock, inversion analysis of stress and deformation evolution of the surrounding rock, and fine support design methods and related theories. SUMMARY

[0004] To solve the problems of narrow installation space, difficult installation, serious hole collapse, serious water vapor and dust invasion, and rough hole wall abrasion in the process of installing the in-hole stress and strain monitoring equipment in the tunnel, roadway and other underground engineering complex surrounding rock drilling, the present application is dedicated to developing a kind of three-dimensional strain monitoring system and method for the internal surrounding rock of the tunnel, roadway and other underground caverns based on drilling, which has simple structure, low cost and convenient installation and use.

[0005] The technical means adopted by the present application are as follows:

[0006] A kind of three-dimensional strain in-situ monitoring system in drilling, comprising:

[0007] The installation main rod is used to fix the hole cleaning limiting disc and the diameter expansion directional strain monitoring cylinder to the pre-selected measuring point position;

[0008] The hole cleaning limiting disc is used to clean and scrape the hole wall when the diameter expansion directional strain monitoring cylinder enters the hole, and to ensure that the installation main rod and the diameter expansion directional strain monitoring cylinder are centered in the hole, the maximum diameter of the hole cleaning limiting disc is smaller than the hole diameter but larger than the diameter of the diameter expansion directional strain monitoring cylinder before diameter expansion;

[0009] The diameter expansion anchor plug is used to expand and install the diameter expansion directional strain monitoring cylinder at the measuring point position after the diameter expansion directional strain monitoring cylinder enters the hole;

[0010] The diameter expansion directional strain monitoring cylinder comprises a drilling radial strain monitoring system, a drilling axial strain monitoring system and a positioning and fixing device,

[0011] The drilling radial strain monitoring system comprises four diameter expansion sliders connected in series by double fastening springs, and a radial spring strain gauge is arranged on the outer side of each slider;

[0012] The drilling axial strain monitoring system comprises four diameter expansion fixed blocks connected in series by single fastening springs, and a pair of axial spring strain gauges are connected between the diameter expansion fixed blocks in the same orientation and the diameter expansion sliders;

[0013] The positioning and fixing device is used to fix the positions of the diameter expansion fixed blocks and the diameter expansion sliders of the drilling radial strain monitoring system and the drilling axial strain monitoring system, and comprises a front stop disc and a rear stop disc, the front stop disc and the rear stop disc are connected by four connecting screws.

[0014] Further, the end of the installation main rod is provided with a directional turn-lock chuck, which is used to be fixedly connected with an auxiliary installation push-pull rod.

[0015] Further, the hole cleaning limiting disc is in the shape of a conical disc, and a soft wiping ring is arranged at the outer edge of the hole cleaning limiting disc.

[0016] Further, the diameter-expanding anchor plug is in the shape of a conical tube, and a diameter-expanding anchor plug orientation guide is arranged inside the diameter-expanding anchor plug, so that the diameter-expanding anchor plug does not rotate relative to the installation main rod when being inserted between the installation main rod and the diameter-expanding orientation strain monitoring cylinder.

[0017] Further, the diameter-expanding orientation strain monitoring cylinder is wrapped with an elastic rubber scratch-proof sleeve.

[0018] Further, the inner diameter of the diameter-expanding anchor plug is determined according to the diameter of the installation main rod, and the outer diameter is determined according to the diameter-expanding size requirement of the diameter-expanding orientation strain monitoring cylinder, so that the initial strain value of the radial hole spring strain gauge in the diameter-expanding orientation strain monitoring cylinder is in the range of 1 / 3 of the full scale, and the contact force between the arc top column of the diameter-expanding fixed block and the hole wall can prevent relative sliding.

[0019] Further, a deformation space of more than 5mm is reserved between the front end of the diameter-expanding fixed block in the diameter-expanding orientation strain monitoring cylinder and the front stop disc of the fixing device, so that the two are in a non-contact state before and after the deformation of the axial spring strain gauge.

[0020] Compared with the prior art, the present application has the following advantages:

[0021] 1. Compared with the existing hole wall rock strain monitoring method, the present application does not need to grout the gap between the hole and the monitoring equipment and the surrounding rock during the whole installation and use process, nor does it need to perform special processing such as local hole expansion on the ordinary hole, but realizes the direct coupling contact between the monitoring equipment and the hole wall rock by expanding the diameter of the monitoring equipment, and can effectively ensure the coupling deformation of the monitoring equipment and the hole wall rock, reduce the introduction of uncontrollable factors, on the one hand, improve the monitoring precision of the hole wall rock strain, on the other hand, enhance the convenience of the installation of the hole equipment, reduce the occupation of the construction time and construction resources of the hole strain monitoring, and enhance the applicability and scope of application of the hole strain monitoring method in engineering. It has important significance for the research on the internal stress-strain state and deformation failure development mechanism of the tunnel and roadway surrounding rock.

[0022] 2、The hole cleaning limiting disc is arranged in front of the strain monitoring equipment, which can effectively avoid continuous contact and friction of the strain monitoring equipment with the surrounding rock during installation process, and the elastic rubber scratch-proof sleeve is arranged outside the expansion directional strain monitoring cylinder of the main monitoring equipment, which can minimize the scratch, rub and collision of the rough borehole wall to the monitoring equipment during installation process, thereby ensuring the safety of the monitoring equipment during installation process, and the hole cleaning effect of the hole cleaning limiting disc can provide relatively smooth and clean hole wall condition for the expansion installation of the expansion directional strain monitoring cylinder, thereby further ensuring the coupling deformation effect of the monitoring equipment and the monitoring quality.

[0023] 3、The spring strain gauge element mode is adopted for strain monitoring, and only the spring strain gauge and the expansion fixing block are in follow-up working state after the expansion directional strain monitoring cylinder is expanded and installed, wherein the expansion fixing block is in contact with the expansion anchor plug through two pairs of hemispherical slide nails, which effectively ensures the adaptability of the monitoring system in the humid hole environment, that is, only the waterproof and dustproof measures of the two spring strain gauges are needed in the application, and no long-term rust prevention measures are needed for the remaining accessories, so that the long-term effective monitoring of the strain in the hole can be realized. The effective structure mode can ensure the monitoring effect while reducing the material performance requirements of various accessories of the strain monitoring system for the high-precision monitoring of the strain in the hole, thereby reducing the manufacturing cost of the hole strain monitoring equipment to some extent, improving the monitoring precision and reliability of the monitoring results, and enhancing the convenience of the hole equipment installation.

[0024] 4、The strain monitoring system can be installed in multiple points in the same hole in a series mode, that is, in addition to realizing the stress and strain comparison analysis of the surrounding rock at the same hole depth between different holes, the comparison analysis can also serve the development law research of the stress and strain of the surrounding rock in the tunnel, roadway and other underground engineering with the hole depth. In summary, the main advantage of the strain monitoring system is that it realizes the deformation coupling with the surrounding rock through the expansion form, can ensure the multi-point installation in the hole, and in-situ monitors the three-dimensional strain development law of the surrounding rock in the hole, and has the advantages of simple system structure, convenient installation and low cost, and is more suitable for wide use in complex working conditions such as tunnels and roadways.

[0025] Based on the above reasons, the application can be widely used in the fields of tunnels and underground engineering. BRIEF DESCRIPTION OF DRAWINGS

[0026] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings needed to be used in the embodiments or the prior art description will be briefly introduced. Obviously, the drawings in the following description are some embodiments of the present application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0027] Figure 1 A structure schematic diagram of a directional strain in-hole monitoring system in the specific embodiment of the present application.

[0028] Figure 2 A structure schematic diagram of a main rod installation in the specific embodiment of the present application.

[0029] Figure 3 A structure schematic diagram of a hole cleaning limiting disc in the specific embodiment of the present application.

[0030] Figure 4 A structure schematic diagram of a diameter expansion anchor plug in the specific embodiment of the present application.

[0031] Figure 5 A structure schematic diagram of a diameter expansion directional strain monitoring cylinder in the specific embodiment of the present application.

[0032] Figure 6 A structure schematic diagram of a positioning and fixing device in the specific embodiment of the present application.

[0033] Figure 7 A structure schematic diagram of an elastic rubber scratch-proof sleeve in the specific embodiment of the present application.

[0034] Figure 8 A structure schematic diagram of a spring strain gauge lead wire in the specific embodiment of the present application.

[0035] In the figure: 1, installation main rod; 1-1, positioning stop pin hole (one); 1-2, positioning stop pin hole (two); 1-3, directional guide groove; 1-4, auxiliary installation push-pull rod; 1-5, directional turn-lock clamp; 2, hole cleaning limiting disc; 2-1, hole cleaning limiting disc directional guide strip; 2-2, positioning stop pin hole; 2-3, wire arranging hole (one); 3, diameter expansion anchor plug; 3-1, diameter expansion anchor plug directional guide strip; 3-2, positioning stop pin reserved gap; 4, positioning stop pin (one); 5, positioning stop pin (two); 6, diameter expansion sliding block; 6-1, radial spring strain gauge installation hole; 6-2, directional sliding groove; 6-3, wire arranging hole (two); 6-4, fastening spring installation hole; 6-5, annular wire arranging hole; 6-6, axial spring strain gauge installation hole (one); 7, diameter expansion fixed block; 7-1, arc top column pier; 7-2, hemispherical sliding nail; 7-3, wire arranging hole (three); 7-4, axial spring strain gauge installation hole (two); 8, fastening spring; 9, drilling radial spring strain gauge; 10, drilling axial spring strain gauge; 11, fixed device rear stop disc; 11-1, wire arranging gap (one); 11-2, main rod-anchor plug hole (one); 11-3, connecting screw hole (one); 11-4, directional sliding nail; 12, fixed device front stop disc; 12-1, wire arranging gap (two); 12-2, main rod-anchor plug hole (two); 12-3, connecting screw hole (two); 12-4, fixed device positioning stop pin hole; 13, front and rear stop disc connecting screw; 14, elastic rubber scratch-proof sleeve; 14-1, main rod-anchor plug hole (three); 14-2, wire arranging gap (three); 14-3, column pier hole; 14-4, radial spring strain gauge hole; 14-5, main rod-anchor plug-nail hole; 14-6, connecting screw hole (three); 15, strain gauge signal transmission line. DETAILED DESCRIPTION

[0036] It should be noted that the embodiments in the present application and the features in the embodiments can be combined with each other without conflict. The technical solutions in the embodiments of the present application will be described in detail below with reference to the drawings and in combination with the embodiments.

[0037] In order to make the purpose, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below in combination with the drawings of the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. The description of the at least one exemplary embodiment is actually only illustrative, not as any limitation on the present application and its application or use. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor belong to the scope of protection of the present application.

[0038] It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments in accordance with the present application. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms "comprises" and / or "comprising," when used in this specification, specify the presence of stated features, steps, operations, devices, components and / or combinations thereof, but do not preclude the presence or addition of one or more other features, steps, operations, devices, components and / or combinations thereof.

[0039] The relative arrangement of parts and steps, numerical expressions, and numerical values set forth in the examples are not intended to limit the scope of the application unless specifically so stated. It is also to be understood that the drawings are not necessarily drawn to scale of the actual proportions of the various parts and components shown therein. Techniques, methods, and apparatus known to those of ordinary skill in the relevant art can not be discussed in detail, but should be considered as part of the description of the application. In all examples shown and discussed herein, any specific numerical value should be interpreted as merely an example, and not as a limitation. Other examples of the example embodiments can have different values. It is noted that like numbers and letters on the figures identify like parts throughout the several views, and that the use of "first", "second", and the like do not necessarily denote any order, but rather are simply intended to identify individual elements.

[0040] In the description of the application, it is to be understood that the orientation or positional relationships indicated by terms such as "front", "back", "up", "down", "left", "right", "horizontal", "vertical", "top", "bottom", and the like are generally based on the orientation or positional relationships shown in the drawings, and are used only for the purpose of facilitating the description and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a particular orientation or be constructed and operated in a particular orientation, and therefore should not be understood as limiting the scope of protection of the present application. The orientation terms "inner", "outer" refer to the inner and outer relative to the contour of the parts themselves.

[0041] For ease of description, spatial relative terms such as "above," "over," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation besides the orientation of the device as described in the figures. For example, if the device in the figures is inverted, a device described as "above" or "above" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0042] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0043] like Figures 1-8 As shown, an in-situ monitoring system for triaxial strain in boreholes comprises four parts: a main mounting rod 1, a borehole cleaning limiting plate 2, an enlarged diameter anchor plug 3, and an enlarged diameter directional strain monitoring cylinder (including 6 to 13).

[0044] Preferably, the mounting rod 1 is a circular steel rod, with a directional guide groove 1-3 running the entire length, and positioning stop pin holes 1-2 and 1-2 at fixed positions (determined according to the measuring point) to fix the installation position and direction of the hole clearing limit plate 2 and the expanded diameter directional strain monitoring cylinder (including 6-13). When multiple strain monitoring is required at different depths within the same borehole, the mounting rod 1 cannot be running the entire length; it only needs to be set to a certain length according to the installation requirements of the expanded diameter directional strain monitoring cylinder (including 6-13). In this case, the outer end of the mounting rod 1 needs to be set as a directional rotary lock 1-5 (the lock disengages when rotated clockwise and does not disengage when rotated counterclockwise). At the same time, an auxiliary installation push-pull rod 1-4 needs to be added to assist in pushing the strain monitoring equipment into the measuring point position in the hole to complete the expanded diameter installation. When only one strain monitoring point is set in the same borehole, the mounting rod 1 can be running the entire length in the hole, and it is advisable to set a certain length according to the installation requirements of the expanded diameter directional strain monitoring cylinder (including 6-13) according to the multi-point monitoring method.

[0045] Preferably, the hole cleaning limiting disc 2 is a conical disc, fixed on the positioning stopper hole (one) 1-1 of the front end mounting main rod 1 by the positioning stopper (one) 4, with a diameter slightly smaller than the hole diameter but larger than the diameter of the expansion diameter directional strain monitoring cylinder (including 6-13) before expansion, and a soft wiping ring can be added to the outer edge of the disc to enhance the hole cleaning effect and facilitate hole entry. When the equipment enters the hole, it can achieve the effect of sweeping and cleaning the hole wall for the expansion diameter directional strain monitoring cylinder (including 6-13), while ensuring that the mounting main rod 1 and the expansion diameter directional stress monitoring cylinder (including 6-13) are basically centered in the hole, preventing continuous or severe scratching of the strain monitoring cylinder and the hole wall, and ensuring the safety of the equipment during hole entry and installation.

[0046] Preferably, the expansion anchor plug 3 is a conical top circular pipe, which can ensure that the expansion diameter strain monitoring cylinder (including 6-13) can be safely and smoothly pushed into the strain monitoring position in the hole, and can complete the expansion at this position, ensuring that the strain monitoring elements of the expansion diameter strain monitoring cylinder (including 6-13) can be coupled with the surrounding rock of the hole and deformed together. The expansion anchor plug 3 is in a disengaged state with the expansion diameter strain monitoring cylinder (including 6-13) before the expansion diameter strain monitoring cylinder (including 6-13) is pushed into the hole at the predetermined strain monitoring position, at which time the overall diameter of the expansion diameter strain monitoring cylinder (including 6-13) is smaller than the diameter of the hole, ensuring that the expansion diameter strain monitoring cylinder (including 6-13) can be pushed into the hole at the predetermined strain position. When the expansion diameter strain monitoring cylinder (including 6-13) is pushed into the specified position, the expansion anchor plug is pushed forward and wedged into the gap between the expansion diameter sliding block 6 and the expansion diameter fixed block 7 of the expansion diameter directional strain monitoring cylinder (including 6-13), at which time all the expansion diameter sliding blocks 6 and the expansion diameter fixed blocks 7 expand outward, forcing the devices on the expansion diameter directional strain monitoring cylinder (including 6-13) that need to be coupled with the hole wall to be deformed to press against the hole wall, so that the radial spring strain gauge 9 of the hole axial strain monitoring system and the arc top column 7-1 of the hole axial strain monitoring system are in close contact with the hole wall, achieving the effect of coupling with the hole wall and deforming. In terms of structure, the expansion anchor plug 3 is internally provided with an expansion anchor plug directional guide strip 3-1 matched with the mounting main rod directional guide groove 1-3, ensuring that the expansion anchor plug 3 does not rotate relative to the orientation of the mounting main rod 1 when it is pushed forward and inserted into the gap between the expansion diameter sliding block 6 and the expansion diameter fixed block 7 of the expansion diameter directional strain monitoring cylinder (including 6-13). The front end is conical and has a gentle slope, and is provided with a positioning stopper reserved gap 3-2, to ensure that the expansion anchor plug is not blocked by the front stop disc 12 and the positioning stopper 5 when it is pushed forward to expand.

[0047] Preferably, the expansion diameter directional strain monitoring cylinder (including 6-13) is entirely wrapped in an elastic rubber scratch-proof sleeve 14, which includes three parts: the hole radial strain monitoring system, the axial strain monitoring system, and the positioning and fixing device. The functions and specific structures of each part are as follows:

[0048] First, the borehole radial strain monitoring system: contains four by double-tight spring 8 in series of expansion diameter slider 6, each slider outside the central position is provided with radial spring strain gauge mounting hole 6-1, the mounting hole 6-1 is communicated with the hoop winding hole 6-5, the radial spring strain gauge mounting hole 6-1 is installed with the corresponding radial spring strain gauge 9, and the strain gauge signal transmission line is arranged through each winding hole (6-3, 6-5,) during installation. In addition, the outer end of each slider is provided with a bevel on the inner side (near the borehole end, close to the installation main rod side), which can ensure that the expansion anchor plug 3 can be smoothly inserted between the expansion slider 6 and the installation main rod 1 for expansion installation; The outer end of the expansion slider 6 is provided with a directional sliding groove 6-2 matched with the directional sliding pin 11-14 of the rear stop disc 11 of the fixing device (the directional sliding pin always slides in the directional sliding groove), so that the orientation of each expansion slider before and after installation does not rotate, and the strain monitoring orientation can be determined by the directional guide groove 1-3 of the installation main rod 1. It should be noted that the number of expansion sliders 6 can be increased or decreased according to the test direction division requirements, and in this example, two pairs of expansion sliders 6 are set for orthogonal line division, that is, the borehole wall convergence deformation (strain) in two perpendicular directions is monitored respectively.

[0049] Second, the borehole axial strain monitoring system: the system needs to increase four expansion fixing blocks 7 connected by single-tight spring in series at the inner end (far from the borehole end) of the original borehole radial strain monitoring system, the expansion fixing block 7 and the expansion slider 6 are connected by four pairs of axial spring strain gauges 10, that is, the expansion fixing block 7 and the expansion slider 6 at the same orientation are connected by a pair of axial spring strain gauges 10, and the strain gauge signal transmission line is arranged through the winding hole (6-3, 6-5,) during installation. In addition, the outer side of the expansion fixing block has three pairs of arc top column piers 7-1, which can ensure that the expansion fixing block has good contact and coupled deformation with the surrounding rock after expansion, and the inner side of the expansion fixing block 7 is in contact with the expansion anchor plug 3 through two pairs of hemispherical sliding pins 7-2 (the expansion anchor plug 3 is in contact with the installation main rod 1 before being pushed in), which can minimize the contact force (friction) between the expansion fixing block 7 and the expansion anchor plug 3 in the axial direction of the borehole, improve the strain monitoring precision of the borehole axial strain monitoring system, and also facilitate the expansion anchor plug 3 to be inserted between the expansion fixing block 7 and the installation main rod 1.

[0050] Third, the positioning and fixing device is composed of the front stop disc 12, the rear stop disc 11 and four front-rear stop disc connecting screws 13. The front stop disc 12 is fixed on the installation main rod 1 by inserting the positioning stop pin (two) 5 into the positioning stop pin hole (two) 1-2 and the fixing device positioning stop pin hole 12-4, and the front stop disc 12 is connected with the rear stop disc 11 through the four front-rear stop disc connecting screws 13. The rear stop disc 11 is provided with four protruding directional sliding pins 11-4 on the front side, and the sliding pins 11-4 are matched with the directional sliding grooves 6-2 on the outer end of the expansion sliding block 6. The function of the directional sliding pins 11-4 is to fix the position of the expansion sliding block 6 and the expansion fixing block 7 of the drilling hole radial strain monitoring system and the axial strain monitoring system, so as to ensure that the position of the expansion sliding block 6 and the expansion fixing block 7 does not rotate before and after the expansion. In addition, the front stop disc 12 and the rear stop disc 11 need to reserve corresponding wire arranging apertures (11-1, 12-1) and holes (11-2, 11-3, 12-2, 12-3) according to the wire arranging requirements and the installation requirements.

[0051] Preferably, when the installation main rod 1 is not arranged longitudinally in the drilling hole, the length of the installation main rod 1 exceeding the clear hole limiting disc at the front end is basically equal to the length remaining in the rear stop disc 11 at the rear end, so as to keep balance.

[0052] Preferably, the inner diameter of the expansion anchor plug 3 is determined according to the diameter of the installation main rod 1, and the outer diameter is determined according to the expansion size requirement of the expansion directional strain monitoring cylinder (including 6-13). The principle is to ensure that the initial strain value of the drilling hole radial spring strain gauge 9 in the expansion directional strain monitoring cylinder (including 6-13) is in the range of 1 / 3 of the range, and at the same time, the contact force between the arc top column 7-1 of the expansion fixing block 7 and the drilling hole wall can be increased to effectively prevent relative sliding between them.

[0053] Preferably, the elastic rubber scratch-proof sleeve 14 needs to reserve corresponding holes (14-1-14-6) according to the expansion directional strain monitoring cylinder installation requirements and wire arranging requirements, and at the same time, the elastic rubber scratch-proof sleeve needs to ensure that the positions of the reserved holes (14-1-14-6) are correct during installation.

[0054] Preferably, when the installation main rod 1 is not arranged longitudinally and the auxiliary installation push-pull rod 1-4 is added, the auxiliary installation push-pull rod 1-4 needs to be strictly prevented from rotating clockwise during the process of pushing the strain monitoring equipment into the hole and the expansion installation process, so as to avoid the disconnection of the directional rotation locking chuck 1-5 (the chuck is disconnected when rotating clockwise, and the chuck will not be disconnected when rotating counterclockwise).

[0055] Preferably, a reserved deformation space of more than 5mm is reserved between the front end (far from the hole end) of the expansion fixing block 7 in the expansion directional strain monitoring cylinder and the front stop disc 12 of the fixing device, that is, to ensure that the two are in a non-contact state before and after the axial spring strain gauge deforms.

[0056] Preferably, the borehole radial spring strain gauge 9 for borehole radial deformation monitoring is a sealed dustproof and waterproof spring strain gauge that can adapt to large (5mm-10mm, compression) deformation, the pressure head of the strain gauge in contact with the hole wall is arranged in a circular arc shape, and the use is to install it in the radial spring strain gauge mounting hole to ensure good contact and coupling deformation between it and the hole wall; the borehole axial spring strain gauge 10 for borehole axial strain monitoring is a sealed dustproof and waterproof spring strain gauge that can adapt to deformation of-5mm to +5mm (compression + tension), and in use, it is installed in the corresponding axial spring strain gauge mounting hole of the diameter expansion sliding block 6 and the diameter expansion fixed block 7.

[0057] Another aspect of the embodiment of the application presents the use process of the above-mentioned monitoring system, which includes:

[0058] The diameter expansion sliding block 6, the diameter expansion fixed block 7, the fastening spring 8, the borehole radial spring strain gauge 9, the borehole axial spring strain gauge 10, the front stop disc 12 of the fixing device, the rear stop disc 11 of the fixing device, and the front-rear stop disc connecting screw 13 are sequentially assembled into a diameter expansion directional strain monitoring cylinder (containing 6-13), the wire arrangement and wiring of the corresponding strain gauge signal transmission line 15 are completed, and the elastic rubber scratch-proof sleeve 14 is sleeved, the strain gauge signal transmission line is connected to the monitoring equipment to test whether the elastic strain gauge is working normally.

[0059] ②The hole cleaning limiting disc 2 is fixed on the positioning stop pin hole (one) 1-1 at the front end of the installation main rod 1 by the positioning stop pin (one) 4.

[0060] ③The diameter expansion directional strain monitoring cylinder (containing 6-13) is fixed in the fixed direction on the positioning stop pin hole (two) 1-2 at the rear end of the installation main rod 1 by the positioning stop pin (two) 5, and the diameter expansion anchor plug 3 is sleeved on the installation main rod 1.

[0061] ④The equipment is pushed into the predetermined borehole strain in-situ monitoring position, and multi-point strain monitoring or only single-point strain monitoring but the installation main rod 1 is not set in length can be applied to the auxiliary installation push-pull rod 1-4, and when the hole depth is large, the segmented auxiliary installation push-pull rod 1-4 can be used.

[0062] ⑤The auxiliary installation push-pull rod 1-4 (when the installation main rod 1 is not usually set) or the installation main rod 1 (when the installation main rod 1 is set in length) is sleeved on the installation main rod 1 by using an ordinary steel pipe (when the hole depth is large, a segmented joint steel pipe can be used), the diameter expansion anchor plug 3 can be inserted between the diameter expansion sliding block 6, the diameter expansion fixed block 7 and the installation main rod 1 for diameter expansion installation, and after completion, the steel pipe is pulled out, the auxiliary installation push-pull rod 1-4 is unlocked by rotating the auxiliary installation push-pull rod 1-4 clockwise to release the directional rotation locking clamps 1-5, and then the auxiliary installation push-pull rod 1-4 is pulled out, at this time, the installation of the borehole strain monitoring system at the measuring point has been completed.

[0063] ⑥ Connect the strain gauge signal transmission line 15 to the monitoring device to monitor the initial strain value of the spring strain gauges (9 and 10).

[0064] ⑦ When multi-point strain monitoring at different depths in the same borehole is required, then the installation is completed from the inside to the outside at the deep part of the borehole according to the steps ①-⑥, and the strain gauge signal transmission line 15 is threaded through the wire arranging holes and the wire arranging openings in series to lead out of the borehole mouth.

[0065] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application, and are not limited thereto; although the present application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that the technical solutions recorded in the foregoing embodiments can still be modified, or some or all of the technical features can be replaced by equivalents; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present application.

Claims

1. A triaxial strain in-hole monitoring system, characterized by, The application relates to a borehole diameter expansion directional strain monitoring device. The device comprises the following parts: an installation main rod for fixing a hole cleaning limiting disc and a diameter expansion directional strain monitoring cylinder to a preselected measuring point position; the hole cleaning limiting disc is used for cleaning and scraping the borehole wall when the diameter expansion directional strain monitoring cylinder is inserted into the borehole, and the hole cleaning limiting disc is used for ensuring that the installation main rod and the diameter expansion directional strain monitoring cylinder are centered in the borehole; the maximum diameter of the hole cleaning limiting disc is smaller than the diameter of the borehole but larger than the diameter of the diameter expansion directional strain monitoring cylinder before diameter expansion; a diameter expansion anchor plug is used for diameter expansion installation of the diameter expansion directional strain monitoring cylinder at the measuring point position after the diameter expansion directional strain monitoring cylinder is inserted into the borehole; the diameter expansion anchor plug is in a conical circular tube shape, and an internal diameter expansion anchor plug directional guide strip is arranged in the diameter expansion anchor plug, so that the diameter expansion anchor plug does not rotate relative to the installation main rod when the diameter expansion anchor plug is inserted into the installation main rod and the diameter expansion directional strain monitoring cylinder; the diameter expansion directional strain monitoring cylinder is entirely wrapped by an elastic rubber scraping sleeve, and comprises a borehole radial strain monitoring system, a borehole axial strain monitoring system and a positioning and fixing device, the borehole radial strain monitoring system comprises four diameter expansion sliders connected by double fastening springs, and each slider is provided with a radial spring strain gauge outside; the borehole axial strain monitoring system comprises four diameter expansion fixed blocks connected by single fastening springs, and the diameter expansion fixed blocks in the same direction are connected by a pair of axial spring strain gauges between the diameter expansion sliders; the positioning and fixing device is used for fixing the positions of the diameter expansion fixed blocks and the diameter expansion sliders of the borehole radial strain monitoring system and the borehole axial strain monitoring system, and comprises a front stop disc and a rear stop disc, and the front stop disc and the rear stop disc are connected by four connecting screw rods; the inner diameter of the diameter expansion anchor plug is determined according to the diameter of the installation main rod, and the outer diameter is determined according to the diameter expansion size requirement of the diameter expansion directional strain monitoring cylinder, so that the initial strain value of the borehole radial spring strain gauge in the diameter expansion directional strain monitoring cylinder is in the range of 1 / 3 of the range, and the contact force between the arc top column of the diameter expansion fixed block and the borehole wall can prevent relative sliding between the arc top column and the borehole wall; 2. The in-situ monitoring system for three-dimensional strain in boreholes according to claim 1, characterized in that, more than 5mm deformation space is reserved between the front end of the diameter expansion fixed block in the diameter expansion directional strain monitoring cylinder and the front stop disc of the fixing device, so that the front end and the rear stop disc are in a non-contact state before and after the axial spring strain gauge is deformed.

3. The in-situ monitoring system for three-dimensional strain in boreholes according to claim 1, wherein, The end of the installation main rod is provided with a directional rotary locking chuck, and the directional rotary locking chuck is used for fixedly connecting an auxiliary installation push-pull rod. The hole cleaning limiting disc is in a conical disc shape, and a soft wiping ring is arranged on the outer edge of the hole cleaning limiting disc.

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